1. Field of the Invention
This invention relates to a quaternary ammonium salt of a copolymer. More especially this invention relates to the use of a quaternary ammonium salt of a copolymer as a detergent for fuels, especially gasoline. This invention is particularly concerned with use of such quaternary ammonium salt of such copolymer not only to remove deposits on an engine carburetor but to prevent deposit build-up on an engine carburetor.
2. Discussion of the Prior Art
Various detergents have been proposed for use in fuels, especially gasoline. For instance, it has heretofore been proposed to employ as a gasoline detergent a condensation product of a secondary C.sub.10 amine with maleic anhydride. Similarly, it has been proposed to use an amine polyisocyanate detergent. Both of these known types of gasoline detergents are effective in removing deposit build-up upon an automotive engine carburetor. However, the known commercially available types of gasoline detergents are particularly costly in production, thus adding to the cost of the final gasoline product at the pump.
It has become desirable, therefore, to provide a less expensive, yet effective, gasoline detergent. It has heretofore been proposed by Catlin et al in U.S. Pat. No. 2,737,452 to use as a fuel oil stabilizer at least 0.001 percent by weight of an oil soluble, basic amino nitrogen-containing addition type polymer of a plurality of polymerizable ethylenically unsaturated compounds, at least one of which is amine-free and contains about 18 carbon atoms in an aliphatic hydrocarbon chain which, while in the polymer, is not part of the main polymer chain. The polymer also contains units which supply a basic amino nitrogen in the side chain, the polymer containing 0.1 to 3.5 percent by weight of basic amino nitrogen. The basic amino nitrogen is supplied by a compound such as .beta.-diethylaminoethyl methacrylate. Such stabilizers are effective in stabilizing catalytically cracked fuel oils. They also possess some degree of detergency.
These stabilizers can be produced at substantially less cost than stabilizers such as a maleic acid-secondary C.sub.10 amine condensation product of amine polyisobutylene.
It has become desirable, however, to provide a gasoline detergent having greater efficacies than those heretofore proposed by Catlin et al. More especially, it has become desirable to provide a gasoline detergent which not only removes deposit build-up from an engine carburetor, but inhibits the build-up of such deposit on such carburetor.